Triethylamine → Tert-butyl (1-(3-methyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-YL)isoxazol-5-YL)cyclopropyl)carbamate

Participants

Reaction Conditions

Reaction Steps

To a 50 mL round bottom flask containing tert-butyl 1-(4-bromo-3-methylisoxazol-5-yl)cyclopropylcarbamate (0.219 g, 0.621 mmol) was added dichlorobis(acetonitrile)palladium(II) (0.0025 g, 9.64 μmol), dicyclohexyl(2′,6′-dimethoxybiphenyl-2-yl)phosphine (0.0134 g, 0.033 mmol), followed by anhydrous 1,4-dioxane (0.40 mL). The reaction vessel was evacuated and purged with N2 (g) (3×). To the flask was added 4,4,5,5-tetramethyl-1,3,2-dioxaborolane (0.153 mL, 1.056 mmol) and triethylamine (0.294 mL, 2.113 mmol) sequentially. The reaction vessel was evacuated and purged with N2 (g) again, then heated to 100° C. The reaction mixture became heterogeneous and was judged complete within 1 h by LC-MS. The heterogeneous mixture was cooled to room temperature, dilute with EtOAc and the mixture was filtered over a plug of Celite. The filter cake was rinsed with EtOAc (3×) and the filtrate was concentrated to give a yellow oil, that crystallized upon standing under vacuum. The product tert-butyl 1-(3-methyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)isoxazol-5-yl)cyclopropylcarbamate (0.226 g, 0.620 mmol, 100% yield) was used without further purification. LC/MS m/z 365 [M+H]+.

Provenance & Evidence